FIG. 1 is an example of the plasma system and plasma configuration of the prior art. Two parallel conducting plates, a top plate (aa) and a bottom plate (bb) with terminals for connection (a) and (b) to the voltage supply is shown. The top plate has uniformly placed apertures (ee) forming a shower head structure. Plasma is struck between the electrodes (aa) and (bb) using either a DC voltage, an AC (or RF) voltage or a pulsed voltage waveform applied to terminals (a) and (b). The gas mixture (f) for the processing passes through the orifices or apertures (ee) of the shower head providing uniform reaction capability in the plasma chamber when plasma C is on between the electrodes (aa) and (bb). The substrate (d) to be processed sits encased in the plasma during processing. The gas mixture (f) and the plasma conditions, like pressure, applied voltage, bias provided etc. define the process accomplished. The processing itself can be a cleaning process, an etching process, a deposition process or a process for chemical functionalization of surfaces.
The shown exemplary prior art processes have a number of problems. They include:                a) When a plasma (c) is lighted (initiated) the gas mixture supplied through the orifices (ee) in the second conducting electrode (aa) to the chamber is ionized, that is there are positive and negative particles that exist in the plasma (c) and depending on the applied voltages they are accelerated towards the electrodes with energy. When the energetic ions strike the substrate (d) they accomplish the process operation, but when the opposite charged particles strike the other electrode (aa), there is unwanted energy transfer to the electrode. Depending on the energy these ions can sputter material from the electrode (aa) which can then get deposited on the substrate (d) and contaminating the substrate (d). Since the energy of the ions is a random vector, it is not possible to completely eliminate this contamination due to electrode sputtering in the prior art plasma configuration.        b) During plasma processing the mixed gases (f) are being delivered to the plasma chamber (c) through the apertures (ee) in the second plate electrode (aa). Since the plasma (c) extends across the gap between the top and bottom electrodes there is possibility of chemical reactions at the second electrode (aa). These reactions can result in formation of particulates that can then be attracted to the substrate (d) and stick to the substrate creating unwanted particle on substrate. This can result in increased defect density and low yield of processed substrate.        c) Since the chemical reactions can happen in the plasma at the shower head which is the second electrode (aa), there is a possibility of the reactants accumulating on the shower head or second electrode (aa). This can lead to the apertures (ee) in the second electrode (aa) getting blocked during processing, resulting in non-uniformity of the process gas supply and gas stream (flow) modification. This in turn can make the process out of control leading to un-wanted results and yield loss on the processed substrate. This can also necessitate frequent cleaning and replacement of the second electrode (aa), which forms the shower head, increasing the process cost.        